Electrophoresis sequencers have been provided with a gel plate assembly, usually precisely vertically mounted, and a buffer tank at the top and bottom. On the device called the BRL Model S2, manufactured by Bethesda Research Labs, Gaithersburg, MD, the top buffer tank is part of the support against which the gel plate assembly is clamped. The bottom tank, though removable, provides no significant contribution to holding the gel plate assembly in place. As a result, separate clamping elements have to be individually pulled and/or rotated and released to hold the vertically oriented gel plate assembly from tipping over. Such clamping elements are tedious and time-consuming in their use, particularly if more than four per plate assembly are required. The tedium is enhanced by reason of the fact that, until the clamps are properly secured, the gel plate assembly has to be manually held from tipping over.
Still another problem with top buffer tanks that are integral with the support, is that they are difficult to clean. Autoclaving is an effective decontamination step, except that when the buffer tank is part of the entire electrophoresis device, and not removable therefrom, it is not feasible to autoclave the top buffer tank by autoclaving the entire device.
Yet another problem with the conventional vertical electrophoresis devices is that the upper buffer tank, by reason of its fixed location, did not permit gel plate assemblies of varying lengths to be used. Such varying lengths are encountered because some samples require a longer lane for adequate separation. Thus when a different length is needed, one has to obtain an entirely different device, or at the very least, a different plate assembly plus upper buffer tank, rather than use a gel plate assembly of different length on the same device.
Still another problem with conventional electrophoresis devices is that the clamps used to hold the gel plate assembly in place, provide variable amounts of clamping pressure, depending upon how much they wre screwed into place. This leads to, in some cases, insufficient clamping pressure, and to compensate for this, in some cases too much pressure that damages the assembly.